1. Field of the Invention
The present invention relates to a nitride light emitting device and a manufacturing method of the same, and more particularly, to a nitride light emitting device including an n-electrode, which exhibits high light transmittance and superb electrical characteristics, and a manufacturing method of the same.
2. Description of the Related Art
A light emitting diode (LED), as one type of a semiconductor light emitting device, generates light of various colors since electrons and holes are recombined at a junction of p-type and n-type semiconductors when a current is supplied. This LED is greatly advantageous over a filament-based light emitting device. That is, the LED has longer useful life, lower voltage, superior initial driving characteristics, high vibration resistance and high tolerance to repetitive power connection/disconnection. This has continually boosted demand for the LED. Notably, of late, a group III nitride semiconductor capable of emitting light at a short wavelength such as blue light has been highlighted.
FIG. 1 is a cross-sectional view illustrating a conventional nitride semiconductor light emitting device.
The nitride semiconductor device 10 includes a conductive substrate 14, and an ohmic contact layer 17, a p-type nitride semiconductor layer 13, an active layer 12 and an n-type nitride semiconductor layer 11 sequentially formed on the conductive substrate 14. Also, the nitride semiconductor device 10 includes an n-electrode 16 formed on a top of the n-type nitride semiconductor layer 11.
The nitride semiconductor light emitting device 10 of FIG. 1 is a vertical light emitting device, and accordingly has electrons and holes recombined in the active layer 12 to emit light outward mainly through the n-type nitride semiconductor layer 11.
Here, the holes are injected uniformly to some extent due to the conductive substrate 14 serving as a p-electrode. However, the n-electrode 16 is locally positioned on the top of the n-type nitride semiconductor layer 11, thus preventing the injected electrons from being diffused uniformly through the n-type nitride semiconductor layer 11. Therefore, current is crowded below the n-electrode 16. Here, light generated from the active layer 12 is considerably absorbed by the n-electrode 16. This undermines light emitting characteristics, and decreases an effective area for current flow to thereby degrade electrical characteristics.
Therefore, there has been a demand in the art for a method of manufacturing the LED in which current is distributed uniformly and light generated can be extracted easily.